Rotary compressor



G. B. PETSCHE.

ROTARY COMPRESSOR.

APPLICATION FILED on. 6, 1320.

Patanted fiept. 13, 1921,

chamber against the least pressure.

GUSTAV B. PETSCHE, 0F YONKERS, NEW Y0.

ROTARY COMPRESSOR.

innate.

' Specification of Letters Patent.

Application filed October 6, 1920. Serial No. 415,145.

To all whom it may concern:

Be it known that I, GUSTAV B. Persona, a citizen of the United States of America, and resident of Yonkers, in the county of Westchester, in the State of New York, have invented a certain new and useful Improvement in Rotary Compressors, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

My invention relates to rotary compressors and particularly, to compression pumps of the type in which the piston consists of an eccentric ring provided with a slide extension moving through a swivel block and separating the admission from the delivery side of the pump. As heretofore constructed the slide extending from the piston has sometimes been formed with a passage or port leading through it for the delivery of fluid from the pump cylinder. This con struction has certain advantages but has a pronounced disadvantage in that the slide pulsates within the delivery chamber and the more or less high pressure fluid therein exerts its full pressure against the end of the slide and through it on" the eccentric and shaft bearings. Also the swivel block is permanently under high ressure in one direction, which is unfavora le for lubrication causing much friction and rapid wear of block and slide. The ob'ect of my invention is to utilize the slide to orm therein the ad mission port of the compressor pump and have the slide work in and out in the suction The advantage oi this is that the only pressure causing friction and wear correspond to the successively increasing pressure in the cylinder, which is zero at the beginning, moderately low for the greater part of the cycle and only high at the end. Thus all moving parts are subject to pulsating pressures,

which as has been found in practice greatly facilitates lubrication andc'onsequently reduces the wear. Also the whole machine gives a better mechanical eficiencv as it takes less power to drive it. With the inlet port in the slide I combine a cut ofi" valve mechanism which will prevent back flow through the portduring the interval when the piston is not in contact with the cylinder walls and I provide the compressor with a delivery valve mechanism which will be open during oy a portion of the compressing cycle of the piston and closes at the end of the compressing cycle.

The nature of my improvements will be best understood as described in connection with the drawings in which they are illustrated and in which- Figure 1 is a side elevation of a compressor pump taken on the section line 11 of Fig. 2.

Fig. 2 is a front elevation partly in section on the line 2-2of Fig. 1, and

Fig. 3 is a detail showing the position of operative parts at the end of the compression cycle of the piston.

A, A, indicate a pair of pump cylinders formed in the same casting inclosed by end plates A A". B is the cylindrical periphery of the cylinder A interrupted at B, B to give the necessary space for the play of the piston slide to be described. In the casting in which the cylinders are formed 1 also form a cylindrical bearing C for a swivel block and on the delivery side of the pump I forin a deliver port D leading into a receiving chamber l on the side of the bearing C. E, E, is the admission chamber of the ump or compressor. F is the driving sha t to which are secured eccentrics F having upon them the eccentric ring pistons G from which extend the slides H fitting in bearings formed in the swivel block indicated at l. The slide H extends, as shown, into the admission chamber E of the pump and is formed with an admission passage opening into the chamber E and opening through a port H into the admission side of the pump. lie the swivel block the edge I of which is so located with regard to the port H that it will close said port as shown in Fig. 3 during the period intervening between successive operative cycles of the piston. l is a port formed in the bearing surface of the swivel block 1: and having an inner wall I so located that the delivery port D will be closed by the oscillation of the swivel block during a portionof the compression cycle of the piston and after the compression cycle is completed during the period intervening between compressing cycles of the piston.

In operation the fluid enters from the admission chamberE through to port H, H, during the revolution of the piston beginning at or slightly after the point when the piston comes in contact with the cylin- Patented Sept;- ie, 1921.

der at or about the point B at or shortly after which point the port H begins to open by moving down below the edge of the swivel block. The fluid contained in the cylinder and lying on the other side of the point of contact of the piston, with the cylinder is being compressed and the delivery port D is closed by the swivel block until. the piston has reached a determinedpoint after which the delivery port is opened and remains open until the piston reaches the position indicated in Fig. 3 when the delivery port is again closed and remains closed while the piston is moving from the position indicated in Fig. 3 to the position predetermined for the discharge.

It will be observed that during the passage of the piston from the point indicated in Fig.3 until it contacts with the cylinder at the point B the piston is out of contact with the peripheral wall of the cylinder but during this period the port H is closed by contact with the swivel block so that no back flow can occur through the admission port when the reexpansion of the compressed air or gas left in the clearance space takes place. This feature is of great value concerning the volumetric efiiciency of the compressor. The advantage of the construction indicated in the drawing is that it enables me to construct the compressor with very small clearances on-the delivery side and involves comparatively small pressure on the swivel block on the delivery side.

Having now described my invention, what I claim as new and desire to secure by Letters Patent; is:

1. A rotary compressor having an eccentric ring piston provided with a slide extension having formed through it a passage teserve as the admission port of the compressor in combination with a swivel block serving as a guide for the slide and as a closure for the admission port in the slide during the interval between the operative cycles of the piston, the port in the slide and the closing surface of the swivel block being so positioned and interrelated that the port is open during substantially the whole operative cycle or the piston, a delivery port leading from the cylinder and valve mechanism timed to close said deliver port except during the latter portion 0' cycle of the piston and at the end of said cycle.

2. A rotary compressor having an eccentric ring piston provided with a slide extension having formed through it a passage to serve as the admission port of the compressor in combination with a swivel block serving as a guide for the slide and as a closure for the admission port in the slide during the interval between the operative cycles of the piston, the port in the slide and the closing surface of the swivel block being so the compression positioned and interrelated that the port is open durin substantially the whole operative cycle 0% ing from the cylinder located in operative relation to a port formed in the swivel block. and so as to be closed by said swivel block during a portion of the compressi n cycle and at the end of said cycle.

3. in a rotary compressor a casing comprising a cylinder chamber, an admission chamber and a bearing for an oscillating swivel block located between said chamber in combination with a swivel block having formed through it a slide bearing, an eccentrio ring piston having a slide extension extending througlfthe swivel block into the admission chamber and formed with an ad mission port extending from its end in the admission chamber and opening through its side, said side opening of the admission port being located as described and so that it will be closed by the swivel block during the interval between the operative cycles of the piston when the piston. is out of contact with the cylinder, a delivery port leading from the cylinder and valve mechanism timed to close said delivery port durin the early portion of the compression cyc e of the piston and at the end of said cycle.

GUSTAV B. PETSCHE the piston, a delivery port lead- 

